Generating documentation from C++ source-to-source compiled code

02 Oct 2023

documentation

Documentation is an essential part of any software project. It helps developers understand how to use, maintain, and extend the codebase. In the case of C++ source-to-source compiled code, where C++ code is transformed into another language, generating accurate and up-to-date documentation can be a challenge. However, with the right tools and practices, it is possible to generate comprehensive documentation for such codebases.

Choosing the Right Documentation Tool

When generating documentation from C++ source-to-source compiled code, it is crucial to select a documentation tool that can parse and understand the transformed code. One popular choice is Doxygen, a widely used tool for documenting C++ code. #C++ #documentation

Configuring Doxygen for Source-to-Source Compiled Code

To configure Doxygen for source-to-source compiled code, we need to provide information about the transformed code and its dependencies, such as the new programming language, library dependencies, and file extensions. This information allows Doxygen to correctly parse and generate documentation for the codebase.

The configuration file for Doxygen, typically named Doxyfile, contains various settings that control the documentation generation process. Some essential settings to consider when documenting source-to-source compiled code include:

EXTENSION_MAPPING: This setting allows mapping of file extensions to the new language’s file extensions, so that Doxygen understands the transformed code.
```
EXTENSION_MAPPING = cpp::<new_extension>
```
FILE_PATTERNS: Update this setting to include the file patterns of the transformed code.
```
FILE_PATTERNS = *.cpp <new_file_patterns>
```
EXCLUDE_PATTERNS: Exclude any files or directories that are not relevant for documentation.
```
EXCLUDE_PATTERNS = <excluded_patterns>
```
INPUT: Specify the directories or files containing the transformed code.
```
INPUT = <directory_or_file_paths>
```

Annotating Source-to-Source Compiled Code

To generate meaningful documentation, it is essential to include proper documentation comments within the source code. Doxygen supports various code documentation styles, including the widely used JavaDoc style and Qt style.

Document your code by adding comments above functions, classes, or variables using the appropriate code documentation style. Additionally, provide detailed explanations of the purpose, parameters, return values, and any other relevant information.

For example, consider the following C++ code using the JavaDoc style:

/**
 * \brief Calculates the sum of two numbers.
 *
 * This function takes two integers as input and returns their sum.
 *
 * \param a The first integer.
 * \param b The second integer.
 * \return The sum of a and b.
 */
int sum(int a, int b) {
    return a + b;
}

Generating the Documentation

Once the Doxygen configuration is set up and the code is properly documented, it’s time to generate the documentation. Run Doxygen with the path to the configuration file:

doxygen <path_to_Doxyfile>

Doxygen will parse the source-to-source compiled code, generate HTML, PDF, or other formats, and store them in the output directory specified in the configuration file.

Conclusion

Generating documentation from C++ source-to-source compiled code is a valuable practice to ensure code maintainability and to help new developers understand the codebase. By choosing the right documentation tool, configuring it appropriately, and annotating the code effectively, we can generate comprehensive and meaningful documentation. With accurate documentation, developers can navigate, understand, and extend the transformed codebase with ease.